Pneumatic hammer.



E. W. RAIKES. PNEUMATIG HAMMER. APPLICATION FILED AUG. 2s, 1909.

Patented Apr. 19, 1910.

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E. W. RAIKES.

PNEUMATIO HAMMER.

APPLIUATION FILED AUG. 2a, 1909.

955,686, Patented Apr. 19, 1910.

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PNEUMATIC HAMMER.

To all whom it may concern:

Be it known that I, EDMOND W. RAIIiEs, a citizen of the United States,residing at- Cleveland, in the county of Cuyahoga and State of Ohio,have invented a certain new and useful Improvement in Pneumatic Hammers,of which the following is a full, clear, and exact description,reference being had to the accompanying drawings.

This invention relates to pneumatic hammers, the same being animprovement upon the hammer shown in Patent No. 155,802, granted July24th, 1906 to J. M. an WV. Raikes.

The obj eet of said improvement is to render the hammer more elieientand to make the same susceptible to regulation of speed, whereby thenumber of blows delivered by the hammer in any given time, as Well asthe force of the blows may be increased or diminished at the will of theoperator.

In the drawings forming a part hereof, Figure 1 is a longitudinalsection taken through the hammer on the line 1-1 of Fig. 2; Fig. 2 is acentral longitudinal section taken vertically through the showing inFig. 4; Fig. 3 is a side elevation of the hammer complete; Figs. 4:, 5,6, and 7 are transverse sectional views taken through the hammer ondifferent planes, as indicated by the correspondingly numbered lines inFig. 1; Fig. 8 is a longitudinal sectional view through a part of thehammer, said View being taken on the line 8 8 of Fig. 5, and Fig. 9 is aside elevation of the valve casing.

Taking up a fuller description by the use of reference characters, 1represents the barrel of the hammer, the same being cast integrally witha part 2 which I shall designate the head. 3 represents the handlepiece, which is adapted for attachment to the head, as shown in Figs. 2and 3. While this handle piece may be attached in any suitable manner, Iprefer to form the same in a general U-shape, the arms -1 of the handlepiece extending over the outer edges of the head and having guide ribs 5and 6 at the rear and front of the head respectively. Also cast integralwith the barrel and head and extending forwardly along side the barrelis an enlarged portion 7, the same being bored to form a chamber for thevalve easing, hereinafter more specifically referred to. Extendingcentrally through the barrel 1 is the bore 8, in which the piston 9reciprocates. At the outer end of the said Specification of LettersPatent.

Application filed August 28, 1909.

Patented Apr. 19, 1910.

Serial No. 515,019.

bore 8 is the die member 10, said member having the stem 11 projectinginto the bore,

the member being held to the barrel in any` suitable manner, as by apressed metal sleeve 12 surrounding the said member and engaging in agroove in the outer end of the barrel, as shown in Fig. l. At the rearoi' handle end of the barrel, the bore 8 is closed by means of a screwthreaded plug 13.

Extending loiwitudinally through the wall of the barrel from the rearend to a point 14 just at the rear of the stem 11 of the die member is aport 15, the same being indicated in dotted lines in Figs. 1 and 2, andthe rear end of the port being closed by a plug 1G, as is indicated indotted lines in Fig. 2. IVithin the bore of the enlargement 7, is a.valve casing 17, the same being shown in detail View in Fig. 9. The borefor the valve casing is of substantially uniform diameter throughout itslength, the forward part of the bore being provided with an opening at18 to form an exhaust port. Adjacent the port 18, the bore for theValve, which I shall term the valve center, is enlarged, as shown at 19,said enlarged portion communicating with the port 15 through a port 20,see Fig. 7, whereby the valve chamber may be placed in directcommunication with the bore 8 of the barrel near the forward end thereofthrough the said port 15. The valve casing 17 1s also provided with acentral longitudinal bore 21, in which reciprocates the automatic valve,said valve having three pistons 22, 23 and 21, the pistons 22 and 23occupying the larger part of the bore of the casing and the piston 251.occupying a smaller portion of said bore.

Opposite the enlarged part 19 of the valve chamber the easing isprovided with a series of radial ports 25, see Fig. 7, the piston 24: ofthe valve being adapted to control these ports. Near its longitudinalcenter, the bore for the valve casing is again enlarged, as shown at 26,and this enlarged portion communicates directly with the bore 8 of thebarrel through a passage 27, as appears from Fig. 6. The valve casing isprovided with a series of radial ports 28 which establish communicationbetween the bore of the Valve casing and the said enlargement 26. Therear end of the valve chamber is closed, and the valve casing is held inplace by an exteriorly threaded nut or plug 29, said nut having acentral port 30 therethrough. The

v provided with a jam nut 34. Extending from the peripheral groove.33 inthe plug diagonally through the head of the hammer' 1s a port 35, thesame communicating at its -upper and forward end with a port 36 whichextends longitudinally' through the wall of the barrel and communicateswith the bore in the latter at a point 37. The rear or handle end of theport 36 is somewhat enlarged and is screw threaded for the reception ofa screw valve 38, the inner end of which is of conical shape in order toclose or restrict more or less the effective size of the opening betweenthe ports 35 and 36. The valve screw 38 is prevented from accidentaldisplacement by a jam nut 39. By a proper adjustment of the screw valves31 and 38, the proper size of air passage between the Valve casing andthe port 36 may be secured, and an air chamber formed between the saidscrew. valves, for a purpose hereinafter set forth.

As appears from Fig. 9, the valve casing 17 is provided with a port 40in the side thereof through which air may be admitted, and with a port41 through which air may be exhausted, the latter port communicatingwith an exhaust passage 42 in the enlarged part 7 of the head. Thebarrel 1 is also provided with a plurality of radially extending ports43, these ports being located between the ports 14 and 17 The air issupplied to the hammer through a flexible hose pipe 44 that ispreferably screw threaded through the lower arm 4 of the hammer handleand into the head of the hammer, said pipe communicating with an airpassage 45 in the lower part of the said head. This passage communicateswith an enlarged portion 46 of a bore 47 in the hammer ead, within whichbore I place an admission valve 48, the valve being held in its rear andclosed osition by a spring 49 in the bottom of the ore, the springbearing against the forward end of the valve. The

4 valve 48 is also provided with a central bore extending from its rearend almost through the valve; and, adjacent the rear end of said bore,the valve is provided with a series of radiating ports v50. The forwardend of the bore for the valve is closed by means of a plug or nut 51,the spring 49 holding the end of the valve against the forward end ofsaid plug. When in this position the ports which the radial ports comv50 are out of register with the enlarged part 46 of the valve bore, andno air can pass into the valve. When, however, the valve is movedforwardly against the tension of the spring, the air may pass throughthe radial ports 50 into the bore within the valve. Leading from theforward part of the bore for the valve is a port 52, the same appearingin Fig. 2 and being indicated in dotted lines in Fig. 6 of the drawings.This port extends across tothe main valve chamber, and registers withthe port 40 in the valve casing 17. The valve 48 is moved forwardlythrough the means ofa stem' 53 that passes through the center of theplug 51, the rear end of the stem engaging with the upper arm 54 of abell crank pivoted in the handle piece, the opposite end 55 beingengaged by the lower end 56 of a lever that is also pivoted in thehandle piece. The upper end 57 of this lever is engaged by the lower endof a lever 58 that is likewise pivoted in the handle piece and has itsupper end 59 projecting outside of said piece so that it may bedepressed by the operator when he wishes to use the hammer.

The operation of the hammer is as follows: Assuming the piston 9 and theautomatic valve to be in the positions shown in Fig. 2, and theadmission valve 48 to be open to admit air to the hammer, the live airentering the port 40 of the valve casing passes outwardly through theports 25 to the ports 2O and 15 and to the front part of the piston,thus driving the piston rear- 100 wardly. This air being atsubstantially full pressure, the piston attains a rapid velocity beforeit uncovers the ports 43 in the barrel. The live air then passesoutwardly through these ports to the atmos- 105 phere. During thegreater part of this time the port 37 is closed by the piston, and airis confined in the valve chamber in the rear of the piston 22 of theautomatic valve, the latter being thus held in 110 what may be termedits (ilosed posltion. During the rearward movement of the piston 9, theair in the bore 8 at the rear of the piston may exhaust freely throughthe ports 27, 28, 41 and 42. The piston 9 hav- 115 ing acquiredsufficient 1nomentum to carry it past the port 37, when this port 1sopened that part of the valve chamber in the rear of the piston 22 mayexhaust through the ports 30, 32, 35, 36 and 43 to the outside air. 120This p'ermits the pressure at the rear of the valve to fall when thelive air pressure on the front of the piston 23 causes the valve toshift to its rear or open position, thus opening communication from thevalve 125 chamber directly through the ports 28 and 27 to the bore ofthe barrel to drive the piston 9 toward the die member, the air in frontof the piston escaping first through the ports 43 land then through theports 14, 13C

15, 20, 25 and 18 to the atmosphere. YVhen the piston 9 has movedforwardly until the port 37 is. uncovered, the live air pressure in thebore 8 acts backwardly through the ports 36, 35, 32 and 30 on the rearend of the valve piston 22, and forces the valve to its forward orclosed position, as shown in Fig. 8. The blow of the piston9 upon thedie member is sufficient to cause the piston to rebound slightly andthus uncover the port 14: so that the live air may again enter in frontof the piston, after which the cycle of operation just described isrepeated, and said operations are continued in more or less rapidsuccession as long as the air is supplied through the valve 48.

By regulating the positions of the screw valves 38 and 31, the rapidityof operation of the reciprocating valve may be controlled, and therapidity of operation of the piston, the length of stroke and the forceof the blow delivered by the piston may likewise be controlled.

It will be observed by reference to Fig. 1 that, when the piston 9 is inthe position therein shown, the port 37 is uncovered. This establishescommunication through the ports 3G, 35, 32 and 30 to the rear face ofthe valve piston 22, so that the pressure in the valve casing at therear of said piston tends to fall, it being remembered that at this timethe rear end of the bore 8 is in communication with the atmospherethrough ports 27 28, 41 and 42. The valve has not been shifted to theposition shown, however, until the said` port 37 has been uncovered andthe live air has had time to act on the valve piston 22. Before thevalve shifts forwardly, therefore, the air pressure in the compressionchamber between the screw valves 31 and 38 has risen so high that itwill not have sufficient time to fall to a pressure which will permitthe valve to be again shifted rearwardly before the piston 9 has movedrearwardly, and has again covered the port 37. This compression chamber,therefore, acts as a kind of reservoir for compressed air and affords ameans for regulating the rapidity of operation of the valve. Byadjusting the screw valves 31 and 38 the effective size of the airpassage between the ports 30 and 36 may be regulated, and the desiredspeed of operation, as well as the desired force of blows delivered, maybe secured. In practice, the

rougher adjustment may be made by the valve 38, and the finer adjustmentsecured by the valve 31.

lVhen the hammer is out of use for some time the piston 9 may moverearwardly beyond the port 27 so as to close the latter. In order toadmit air to the rear of the piston in such contingency, I-cut a groovein the wall formino' the bore 8 said groove being shown in tIig. 2 at 60and leading from the port 27 rearwardly to the plug 13. While thisgroove is quite small, it will admit sufficient air to the rear of thepiston to force the same forwardly until the port 27 is uncovered. Ialso extend a small port rearwardly through the rear end of the valve 48so that there will be no vacuum formedV at the rear of said valve whenthe same is moved forwardly, and also to permit the air which may becontained at the rear of the valve to escape when the same is movedrearwardly under the tension of the spring 4:9. This port is indicatedin dotted lines in Fig. 2 by reference numeral 61.

Having thus described my invention, what I claim is:

l. In a pneumatic hammer, the combination with a barrel having alongitudinal bore therein, of a piston mounted to reciprocate in saidbore, an automatic valve mounted to reciprocate in a valve chamberalongside the rear end of said barrel, the barrel being provided withports leading from the valve chamber to the bore of the barrel, thevalve controlling the operation of the piston, and a pair of adjustablevalves for regulating the eHective size of one of said ports at twodifferent points, whereby air4 may be compressed in that port -betweenthe said adjustable valves for regulating the quantity of air passingthrough said port and thereby regulating the speed of operation of theautomatic valve and of the said piston.

2. In a pneumatic hammer, the combination with a barrel having alongitudinal bore therein, of a piston mounted to reciprocate in saidbore, the said barrel having an enlargement at its rear end and saidenlargement having a longitudinal bore forming a valve chamber, a valvecasing in said chamber, the barrel being rovided with a pair of portsleading from t e bore therein to the valve chamber near the oppositeends of said casing, and with a port connecting the bore in the valvewith the chamber near the center of said casing, an automatic valvemounted to reciprocate in the valve casing, said valve being controlledby the compressed fluid, an exhaust port leading outwardly through thevalve casing and the said enlargement on the barrel, and means foradjusting the effective size of one of the ports leadin from the valvecasing to the bore of the arrel, whereby the movements of the piston maybe regulated.

3. ,In a pneumatic hammer, the combination with a barrel having alongitudinal bore therein, of a plug closing the rear end of said bore,`a piston Within the bore and adapted to reciprocate therein, anenlargement on said barrel having a valve chamber therein, a valvecasing stationarily mounted within the said chamber, said casing havinga bore therethrough and a port extendin outwardly through the casingfrom sai bore, means for conducting compressed iuid to the latter port,an automatic valve mounted to operate in the valve casing, a plugclosing one end of the valve chamber, said plug being provided with aport in its end next to the valve and with a series of ports radiatingfrom the last mentioned port outwardly through the lug, an air passageconnecting the said rac iating ports with the bore in the barrel, asecond air passage leading from the valve chamber to the bore of thebarrel near the forward end of the latter, and a screw passing throughthe plug in the valve chamber for regulating the effective size of theport in the end of said plum 4. In a pneumatic hammer, the combinationwith a barrel and with a head for the same, of a piston mounted toreciprocate in a longitudinal bore in the barrel, the said head andbarrel heilig provided with an enlargement havinfr a longitudinal boretherein forming a vzilve chamber, an automatic valve mounted to operatein said chamber, a screw plug closing the rear end of said chamber, saidplug having a longitudinal port extending therethrough and a series ofradiating ports extending outwardly from the longitudinal port throughthe side of the plug, a screw Within the outer end of the longitudinalport, said screw being adapted to regulate the size of the assagebetween the latter port and the ra iating ports, a port extendinglongitudinally in the wall of the barrel and communicating with the borein the barrel, a diagonal port connecting the longitudinal port in thebarrel with the radiating ports in the plug, and a screw in thelongitudinal port in the barrel, said screw being adapted to act as avalve and regulate the ell'ective size of the passage between the saidport in the barrel and the diagonal port, the diagonal port thus havinga valve at cach of its ends by which the lluid entering the saiddiagonal port may be controlled and the speed of operation of the hammerpiston may be regulated.

In testimony whereof, I hereunto alix my signature in the presence oftwo witnesses.

EDMOND W. RAIKES.

Witnesses S. E. Fours, A. J. HUDSON.

